Campanayuq Rumi is a large civic-ceremonial center located in the south-central highlands of Peru. Founded in the late Initial Period (1100-800 BC), Campanayuq Rumi became an important center within the Chavín Interaction Sphere in the Early Horizon (ca. 800-400 BC). In particular, Campanayuq Rumi is significant because of its geographical proximity to Quispisisa, the most important and widely circulated obsidian source during the Early Horizon. Portable X-ray florescence (pXRF) was used to geochemically source a sample of 370 obsidian artifacts from Campanayuq Rumi. Though obsidian from Quispisisa dominates the assemblage throughout the site's history, diachronic analysis indicates that the diversity of obsidian sources increases markedly in the Campanayuq II Phase (700-450 BC). The pXRF data lead us to conclude that Campanayuq Rumi was the locus of obsidian distribution to other locations in highland and coastal Peru within the Chavín Interaction Sphere, and functioned as a regional center of worship and interaction.